Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China.
Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China.
J Exp Med. 2022 Apr 4;219(4). doi: 10.1084/jem.20212032. Epub 2022 Mar 8.
Many encapsulated bacteria use capsules to cause invasive diseases. However, it remains largely unknown how the capsules enhance bacterial virulence under in vivo infection conditions. Here we show that the capsules primarily target the liver to enhance bacterial survival at the onset of blood-borne infections. In a mouse sepsis model, the capsules enabled human pathogens Streptococcus pneumoniae and Escherichia coli to circumvent the recognition of liver-resident macrophage Kupffer cells (KCs) in a capsular serotype-dependent manner. In contrast to effective capture of acapsular bacteria by KCs, the encapsulated bacteria are partially (low-virulence types) or completely (high-virulence types) "untouchable" for KCs. We finally identified the asialoglycoprotein receptor (ASGR) as the first known capsule receptor on KCs to recognize the low-virulence serotype-7F and -14 pneumococcal capsules. Our data identify the molecular interplay between the capsules and KCs as a master controller of the fate and virulence of encapsulated bacteria, and suggest that the interplay is targetable for therapeutic control of septic infections.
许多包被细菌利用荚膜来引发侵袭性疾病。然而,在体内感染条件下,荚膜如何增强细菌毒力在很大程度上仍不清楚。在这里,我们发现荚膜主要靶向肝脏,以增强血源性感染开始时细菌的存活率。在小鼠败血症模型中,荚膜使人类病原体肺炎链球菌和大肠杆菌能够以荚膜血清型依赖的方式规避肝驻留巨噬细胞库普弗细胞(KCs)的识别。与 KCs 有效捕获无荚膜细菌相反,被包被的细菌部分(低毒力类型)或完全(高毒力类型)对 KCs“不可触及”。我们最终确定了去唾液酸糖蛋白受体(ASGR)作为 KCs 上第一个已知的荚膜受体,以识别低毒力血清型 7F 和 14 型肺炎链球菌荚膜。我们的数据确定了荚膜和 KCs 之间的分子相互作用是被包被细菌命运和毒力的主要控制器,并表明这种相互作用是治疗控制败血症感染的靶向目标。